The present disclosure is generally directed, in various exemplary embodiments, to methods of separating or fractioning polyalkylene materials, such as polyalkylene waxes. The present disclosure also relates to products produced utilizing the separated or fractionated materials, such as phase change inks and toners comprising the same. The resulting products can be selected for known electrophotographic, electrostatographic, xerographic, and like imaging processes, including copying, printing, faxing, scanning, and like machines, and including digital, image-on-image, color, lithography, and like processes.
Polyalkylene waxes are a component used in toners, phase change inks, and other marking materials. Wax properties such as purity, molecular weight distribution, polydispersity, jetting, fusion, etc., are important for the performances of these applications.
For example, polyalkylene waxes, such as polyethylene waxes, having molecular weights Mw less than 1500, preferably less than 1000, are components in mainline high melting and low melting solid inks, respectively. These wax materials have low melting points that allow for low jetting temperatures to be utilized and maintained while also lowering the coefficient of friction.
However, some polyalkylene waxes fail to meet one or more of the desired requirements for waxes. In this regard, wax marking products may exhibit large batch-to-batch variations, high polydispersity indexes (PDI), skewnesses in Mw distribution, etc. These undesired material characteristics create inconsistent results in the marking products.
Some commercially available polyalkylene waxes, such as POLYWAX™ 655 and 500 (Baker-Petrolite Corp.), have wide Mw distributions with carbon chain lengths ranging from about 30 to about 70 carbons (POLYWAX 500) and from about 30 to about 100 carbons (POLYWAX 655). Additionally, these waxes have a high content of low Mw fractions (fractions comprising carbon chain lengths of from about 50 carbons or less). The low Mw fraction in POLYWAX 500 is around 50% by weight, and the low Mw fraction in POLYWAX 655 is around 40% by weight. Low Mw materials lower the onset of wax melting (lower the offset temperature) and also weaken the mechanical strength of the solidified waxes.
Moreover, there are only a limited number of large scale methods available to purify wax material. Distillation is one method typically used to provide fractionated versions of the waxes. For example, some suppliers of the polyalkylene waxes perform distillation processes on the waxes to supply fractionated or semi-fractionated versions and to achieve narrower Mw distributions. These distillation procedures, however, have drawbacks in that they are expensive and generally limited to lower molecular weight materials.
This disclosure is directed to overcoming one or more of the aforementioned problems and/or others.